Despite yo-yoing temperatures in the Tennessee Valley, tomatoes, basil and cilantro have been growing strong at a small shop on Rossville Avenue.

Inside Atlantis Hydroponics, gardeners can find everything they need to grow any type of plant -- except soil. The shop specializes in a type of growing method that uses mineral solution mixed with water to allow plants to grow without the help of dirt.

Since opening its first shop outside the Atlanta area about 2 1/2 years ago here, business has dramatically increased, store manager Phillip Hester said.

"Business was up last year, especially with the price of groceries going up," he said. "People are becoming more and more conscious about what they spend their money on."

Though hydroponics techniques can be used to grow just about any plant, Hester said, the fact that it can be used to grow organic foods at a quicker rate is what makes the process fascinating. He said growing plants hydroponically yields more produce and healthier plants.

Hydroponically grown produce, a $2.4 billion industry growing at a rate of 10 percent each year, is available at most major supermarkets across the country, according to the Progressive Gardening Trade Association. Hester said people are often surprised to learn that much of the produce they buy, especially in the off season, is grown hydroponically.

"It's starting to be a larger industry trend, getting clean food that doesn't travel 1,500 miles to get to you," he said. "With hydroponics, you can pick the tomato the day it's ripe."

Growing plants hydroponically takes a little getting used to since pH levels must closely be monitored, but it doesn't take much time to catch on, Hester said. There is some startup cost, with small grow room tents starting at $150 and a typical full system cost of about $1,000, he said.

"But you can save $20,000 in grocery bills over the lifetime of the system, and if you want a tomato in January, you don't have to go out and buy them," Hester said.

Scott Brown, assistant manager at Atlantis Hydroponics, started learning about plants when he worked on a farm and has picked up on the ins and outs of hydroponics during the seven months he has worked at the shop.

He helps the uninitiated understand soil-free farming by describing it in traditional terms.

"Growing plants without soil might sound kind of crazy, but it works," he said. "You just want to recreate inside what you find outside -- light, air and water. I just try to tie everything back to the outside when I'm explaining it."